/*-
 * Copyright (c) 2016 Jared McNeill <jmcneill@invisible.ca>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Allwinner oscillator clock
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/rman.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <machine/bus.h>

#include <dev/fdt/simplebus.h>

#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>

#include <dev/clk/clk.h>

#include "clkdev_if.h"

#define CCU_BASE        0x01c20000
#define CCU_SIZE        0x400

struct aw_ccu_softc {
        struct simplebus_softc  sc;
        bus_space_tag_t         bst;
        bus_space_handle_t      bsh;
        struct mtx              mtx;
        int                     flags;
};

static struct ofw_compat_data compat_data[] = {
        { "allwinner,sun7i-a20",        1 },
        { "allwinner,sun6i-a31",        1 },
        { "allwinner,sun6i-a31s",       1 },
        { NULL, 0 }
};

static int
aw_ccu_check_addr(struct aw_ccu_softc *sc, bus_addr_t addr,
    bus_space_handle_t *pbsh, bus_size_t *poff)
{
        if (addr >= CCU_BASE && addr < (CCU_BASE + CCU_SIZE)) {
                *poff = addr - CCU_BASE;
                *pbsh = sc->bsh;
                return (0);
        }
        return (EINVAL);
}

static int
aw_ccu_write_4(device_t dev, bus_addr_t addr, uint32_t val)
{
        struct aw_ccu_softc *sc;
        bus_space_handle_t bsh;
        bus_size_t reg;

        sc = device_get_softc(dev);

        if (aw_ccu_check_addr(sc, addr, &bsh, &reg) != 0)
                return (EINVAL);

        mtx_assert(&sc->mtx, MA_OWNED);
        bus_space_write_4(sc->bst, bsh, reg, val);

        return (0);
}

static int
aw_ccu_read_4(device_t dev, bus_addr_t addr, uint32_t *val)
{
        struct aw_ccu_softc *sc;
        bus_space_handle_t bsh;
        bus_size_t reg;

        sc = device_get_softc(dev);

        if (aw_ccu_check_addr(sc, addr, &bsh, &reg) != 0)
                return (EINVAL);

        mtx_assert(&sc->mtx, MA_OWNED);
        *val = bus_space_read_4(sc->bst, bsh, reg);

        return (0);
}

static int
aw_ccu_modify_4(device_t dev, bus_addr_t addr, uint32_t clr, uint32_t set)
{
        struct aw_ccu_softc *sc;
        bus_space_handle_t bsh;
        bus_size_t reg;
        uint32_t val;

        sc = device_get_softc(dev);

        if (aw_ccu_check_addr(sc, addr, &bsh, &reg) != 0)
                return (EINVAL);

        mtx_assert(&sc->mtx, MA_OWNED);
        val = bus_space_read_4(sc->bst, bsh, reg);
        val &= ~clr;
        val |= set;
        bus_space_write_4(sc->bst, bsh, reg, val);

        return (0);
}

static void
aw_ccu_device_lock(device_t dev)
{
        struct aw_ccu_softc *sc;

        sc = device_get_softc(dev);
        mtx_lock(&sc->mtx);
}

static void
aw_ccu_device_unlock(device_t dev)
{
        struct aw_ccu_softc *sc;

        sc = device_get_softc(dev);
        mtx_unlock(&sc->mtx);
}

static const struct ofw_compat_data *
aw_ccu_search_compatible(void) 
{
        const struct ofw_compat_data *compat;
        phandle_t root;

        root = OF_finddevice("/");
        for (compat = compat_data; compat->ocd_str != NULL; compat++)
                if (ofw_bus_node_is_compatible(root, compat->ocd_str))
                        break;

        return (compat);
}

static int
aw_ccu_probe(device_t dev)
{
        const char *name;

        name = ofw_bus_get_name(dev);

        if (name == NULL || strcmp(name, "clocks") != 0)
                return (ENXIO);

        if (aw_ccu_search_compatible()->ocd_data == 0)
                return (ENXIO);

        device_set_desc(dev, "Allwinner Clock Control Unit");
        return (BUS_PROBE_SPECIFIC);
}

static int
aw_ccu_attach(device_t dev)
{
        struct aw_ccu_softc *sc;
        phandle_t node, child;
        device_t cdev;
        int error;

        sc = device_get_softc(dev);
        node = ofw_bus_get_node(dev);

        simplebus_init(dev, node);

        sc->flags = aw_ccu_search_compatible()->ocd_data;

        /*
         * Map registers. The DT doesn't have a "reg" property
         * for the /clocks node and child nodes have conflicting "reg"
         * properties.
         */
        sc->bst = bus_get_bus_tag(dev);
        error = bus_space_map(sc->bst, CCU_BASE, CCU_SIZE, 0,
            &sc->bsh);
        if (error != 0) {
                device_printf(dev, "couldn't map CCU: %d\n", error);
                return (error);
        }

        mtx_init(&sc->mtx, device_get_nameunit(dev), NULL, MTX_DEF);

        /* Attach child devices */
        for (child = OF_child(node); child > 0; child = OF_peer(child)) {
                cdev = simplebus_add_device(dev, child, 0, NULL, -1, NULL);
                if (cdev != NULL)
                        device_probe_and_attach(cdev);
        }

        bus_attach_children(dev);
        return (0);
}

static device_method_t aw_ccu_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         aw_ccu_probe),
        DEVMETHOD(device_attach,        aw_ccu_attach),

        /* clkdev interface */
        DEVMETHOD(clkdev_write_4,       aw_ccu_write_4),
        DEVMETHOD(clkdev_read_4,        aw_ccu_read_4),
        DEVMETHOD(clkdev_modify_4,      aw_ccu_modify_4),
        DEVMETHOD(clkdev_device_lock,   aw_ccu_device_lock),
        DEVMETHOD(clkdev_device_unlock, aw_ccu_device_unlock),

        DEVMETHOD_END
};

DEFINE_CLASS_1(aw_ccu, aw_ccu_driver, aw_ccu_methods,
    sizeof(struct aw_ccu_softc), simplebus_driver);

EARLY_DRIVER_MODULE(aw_ccu, simplebus, aw_ccu_driver, 0, 0,
    BUS_PASS_BUS + BUS_PASS_ORDER_MIDDLE);

MODULE_VERSION(aw_ccu, 1);